The exploration and recovery of hydrocarbons such as oil and gas generally begins with drilling a borehole into a potentially hydrocarbon-bearing geological formation. In many types of drilling operations, it may be desirable to remotely activate one or more downhole tools to perform a desired function. For example, an underreamer may be activated and operated to ream a previously drilled borehole to expand its diameter.
Some tools are remotely activated, by dropping a ball downhole. Such a tool may be designed so that when the dropped ball reaches the tool, the ball engages a seat to close or restrict a flow passage, to pressurize fluid above an activation set point.